Epoxy-Based Interlocking Membranes for All Solid-State Lithium Ion Batteries: The Effects of Amine Curing Agents on Electrochemical Properties

Abstract

In this study, a series of crosslinked membranes were prepared as solid polymer electrolytes (SPEs) for all-solid-state lithium ion batteries (ASSLIBs). An epoxy-containing copolymer (glycidyl methacrylate-co-poly(ethylene glycol) methyl ether methacrylate, PGA) and two amine curing agents, linear Jeffamine ED2003 and hyperbranched polyethyleneimine (PEI), were utilized to prepare SPEs with various crosslinking degrees. The PGA/polyethylene oxide (PEO) blends were cured by ED2003 and PEI to obtain slightly and heavily crosslinked structures, respectively. For further optimizing the interfacial and the electrochemical properties, an interlocking bilayer membrane based on overlapping and subsequent curing of PGA/PEO/ED2003 and PEO/PEI layers was developed. The presence of this amino/epoxy network can inhibit PEO crystallinity and maintain the dimensional stability of membranes. For the slightly crosslinked PGA/PEO/ED2003 membrane, an ionic conductivity of 5.61 × 10−4 S cm−1 and a lithium ion transference number (tLi+) of 0.43 were obtained, along with a specific capacity of 156 mAh g−1 (0.05 C) acquired from an assembled half-cell battery. However, the capacity retention retained only 54% after 100 cycles (0.2 C, 80 °C), possibly because the PEO-based electrolyte was inclined to recrystallize after long term thermal treatment. On the other hand, the highly crosslinked PGA/PEO/PEI membrane exhibited a similar ionic conductivity of 3.44 × 10−4 S cm−1 and a tLi+ of 0.52. Yet, poor interfacial adhesion between the membrane and the cathode brought about a low specific capacity of 48 mAh g−1. For the reinforced interlocking bilayer membrane, an ionic conductivity of 3.24 × 10−4 S cm−1 and a tLi+ of 0.42 could be achieved. Moreover, the capacity retention reached as high as 80% after 100 cycles (0.2 C, 80 °C). This is because the presence of the epoxy-based interlocking bilayer structure can block the pathway of lithium dendrite puncture effectively. We demonstrate that the unique interlocking bilayer structure is capable of offering a new approach to fabricate a robust SPE for ASSLIBs.

Spiro-Twisted Benzoxazine Derivatives Bearing Nitrile Group for All-Solid-State Polymer Electrolytes in Lithium Batteries

“…Both the two samples exhibited a rather higher electrochemical window when compare with the PEO/LiTFSI electrolyte. According to the literature [ 29 , 64 , 65 ], oxidation of the PEO electrolyte starts at approximately 4 V. −C≡N···Li + ···(EO) n coordination can effectively delocalize the lone pair electrons in the EO units. The aforementioned results indicate that the s-IPN-bearing benzyl cyanide group is beneficial for stabilizing the PEG/Li + coordination structure [ 61 ] because of its electron-withdrawing ability.…”

“…The electrochemical performance comparison of SPEs in this work and those reported in the literature is shown in Table S2 [ 29 ],[ 65 ],[ 68 ],[ 69 ],[ 70 ],[ 71 ],[ 72 ] . The SPEs in this work exhibited comparable electrochemical properties for the LIBs.…”

Tough Polymer Electrolyte with an Intrinsically Stabilized Interface with Li Metal for All-Solid-State Lithium-Ion Batteries

“…The result represented that the mechanical property of the thin-film PEO/LiTFSI electrolyte is too low for the charge–discharge test and tends to cause the short-circuit phenomenon, as also reported in the literature . The thicknesses of the PEO/LiTFSI electrolyte decreased drastically when the membranes were assembled and stored at 80 °C for hours …”

“…53 The thicknesses of the PEO/ LiTFSI electrolyte decreased drastically when the membranes were assembled and stored at 80 °C for hours. 54 3.6. Tensile Properties.…”

Glycidyl Methacrylate-Based Copolymers as Healing Agents of Waterborne Polyurethanes

“…Among others, GMA has been combined with the soft and hydrophobic n-butyl acrylate (BA) monomer or poly(ethylene glycol) methyl ether methacrylate (PEGMA) macromonomers leading to materials with low glass transition temperature. Copolymers of GMA and BA have been utilized as latexes or for the reinforcement of epoxy resins [ 38 , 39 , 40 , 41 ], while copolymers of GMA and PEGMA can find use in bioapplications (wound dressings [ 42 ], drug delivery systems [ 43 ], antibacterial nanocarriers [ 44 ], enzyme-polymer conjugates [ 45 ], as solid [ 46 , 47 ] or gel [ 48 ] polymer electrolyte membranes or as coatings for the preparation of modified membranes with antifouling [ 49 ] or heavy metals and dyes separation [ 50 ] properties.…”